NO. 12 PERMIAN BRACHIOPODS FROM OREGON-——COOPER £3 
Kochiproductus transversus Squamularia rostrata (Kutorga) 
Cooper Stenoscisma cf, S. plicatum 
Krotovia pustulata (Kutorga) 
(Keyserling) Waagenoconcha parvispinosa 
Cooper 
S106. SWISE4SW3 sec. 28, T. 18 S., R. 25 E., 24 miles due north of Sherman 
Ranch. 
Alexenia? subquadrata Cooper Probolionia posteroreticulata 
Avonia oregonensis Cooper Cooper 
Kochiproductus cf. K. Squamularia rostrata (Kutorga) 
porrectus (Kutorga) Stenoscisma ci. S. plicatum 
(Kutorga) 
S111. About 4 mile north of center sec. 28, T. 18 S., R. 25 E., 13 miles north- 
west of Mills Ranch. 
Chonetes sp. I Linoproductus cf. L. lutkewitschi 
(Stepanow ) 
CORRELATION OF THE PERMIAN OF OREGON 
Any correlation based on a single group of animals, unless that 
group is an accepted standard of comparison, must be regarded as 
tentative. In view of the fact that goniatites and fusulines at present 
are regarded as the most reliable groups in the Permian, some con- 
flict with a correlation based on brachiopods alone may be expected. 
The brachiopods of the upper Paleozoic are still too little known for 
all the superfamilies represented to be reliable. Furthermore, some 
of the genera such as Composita have few morphological characters 
on the exterior and, at present, are of no value in correlation. Investi- 
gation of the interior of such brachiopods may prove them to be more 
useful but development of the interior will require much skill and 
more time than most paleontologists are willing to give. 
The Permian assemblage from Oregon is a varied one but it con- 
tains a number of genera that can be excluded from consideration 
because of their present slight correlative value. These are Lingula, 
Rhipidomella, Derbyia, Composita, Squamularia, and Hustedia. In 
addition Neospirifer, Crurithyris, and Punctospirifer are added to 
this list, not because of any implied lack of correlative value, but 
because the specimens available are too poor or insufficiently repre- 
sented to use. 
Another special problem in this exercise in correlation is the fact 
that some of the genera and species are unlike any described American 
Permian species. Comparison with European forms, and especially 
Russian ones, is difficult because comparative material does not exist 
in this country. Furthermore the modern illustrations of some of the 
